Conventionally, contact probe modules have been widely used for testing electroconductive patterns of printing circuit boards and various electronic devices, and there have been attempts to modify them into more suitable forms for testing LCD panels. In testing of an LCD panel, it is desirable to test the panel under conditions which closely approximate the actual conditions of the final product. Therefore, it is desirable to test the LCD panel by using a TAB (an LSI chip used for driving an LCD panel) identical to that used in the final product. Because a large number of wires must be connected between the LCD panel and the TAB, the TAB should be incorporated into the contact probe module itself.
With liquid crystal front panel development, size and analysis increases require that the probe module applied to the LCD panel require higher pin count and finer pitch. Currently, LCD analysis technology utilizes two types of probe modules: a needle type and a membrane type. The needle-type probe module, an example of which is generally indicated by reference numeral 10 in FIG. 1, includes multiple probe needles 14 extending from a probe base 12. The probe needles 14 contact respective terminals 20 provided on a panel board 18 of an LCD panel 16.
Use of the conventional needle-type probe module 10 to test the LCD panel 16 requires that the multiple probe needles 14 be individually assembled on the probe base 12, as well as individually adjusted to the probe surface level. This adjustment is time-consuming and laborious. Furthermore, the pitch of the needles is limited to 50 μm. This limits the number of needles which can be provided on the probe base. Because the probes have a low stress tolerance, a common surface level is required for probing. Moreover, when one or more of the pins is damaged, the whole probe needle assembly must be returned to the assembly plant for repair.
The membrane-type of probe module utilizes an electroplating method to fabricate metal bumps or contact points on a membrane. While the membrane-type probe module avoids the complicated assembly procedure of the needle-type probe module, the electroplating method introduces unevenness into the membrane, causing the metal bumps on the membrane to vary in thickness. This adversely affects the surface level performance. Moreover, the height of the bump is typically limited by the fabrication technology to less than about 20 μm. Consequently, the probing ability of the membrane-type probe tip is easily adversely affected by micro-particles in the probing environment.
Another drawback which is associated with the membrane-type probe module is that the membrane on which the bumps are fabricated repeatedly flexes and relaxes throughout repeated use of the unit. Consequently, the membrane has a tendency to fatigue and break or peel from the underlying metal substrate of the probe module. Considerable difficulty has been encountered in developing a membrane material of sufficient elasticity to withstand the flexing and bending pressures of probe testing.
To overcome the drawbacks of the conventional needle-type probe module and membrane-type probe module, the present invention utilizes MEMS (Micro Electrical Mechanical Systems) technology to fabricate probing modules for the testing of LCD panels and related devices. The present invention replaces the complicated traditional manual packaging procedure and provides an ultra-fine pitch and precision locator high hardness probe structure, in addition to increasing the tolerance of the probe tip to environmental particle contamination. The present invention increases the ease of maintenance or replacement of probe tips, thus decreasing cost and increasing the production rate.
An object of the present invention is to provide a new and improved probe module which is suitable for probing LCD panels.
Another object of the present invention is to provide a new and improved probe module which utilizes MEMS technology to fabricate a probe module.
Still another object of the present invention is to provide a new and improved probe module which is characterized by ultra-fine probe pin pitch adjustment and location.
Yet another object of the present invention is to provide new and improved probe pins manufactured using MEMS technology.
A still further object of the present invention is to provide a probe module which has a high tolerance for environmental particle contamination.
Another object of the present invention is to provide a probe module characterized by low cost and high efficiency.
A still further object of the present invention is to provide a probe module characterized by a high-density and high-number pin count and high electrical performance.